IVUS Imaging and Analysis IVUS at baseline, immediately after PCI, and at 6 months will be performed with iLab, Galaxy, and ClearView or In Vision Gold with 20-MHz EagleEye catheters. IVUS imaging will be performed with motorized pullback at 0.5 mm/s to include the stent and >5 mm segments proximal and distal to the stent. IVUS studies will be archived onto super-VHS tape, CD-ROM, or DVD and will be sent to an independent, treatment-allocation- blinded, IVUS core laboratory for quantitative and qualitative analyses with validated planimetry software. Quantitative analysis will include measurement every 1 mm of the external elastic membrane (EEM), stent, and lumen cross-sectional areas (CSAs). Plaque plus media CSA will be calculated as EEM minus lumen. Neointimal hyperplasia (NIH) will be calculated as stent minus lumen. Once a complete set of CSA measurements will be obtained, intrastent and stent-edge volumes (EEM, plaque plus media, stent,lumen, and NIH) will be calculated with Simpson's rule and normalized for stent and reference segment length. Percent net volume obstruction will be calculated as NIH divided by stent volume.